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' B. J. DU BOSE.

GRINDING MILL.

No. 332,143. Patented Dec. 8, 1885.

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N. PEYERS. Photoulhagnpher, Wllhinghm. D. C.

UUNITED STATES PATENT OFFICE.

OF LISBON, GEORGIA.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 332,143, dated December 8, 1885.

Application filed August 3, 1885.

To all whom it may concern:

Be it .known that I, BENJAMIN J. DU Boss, of Lisbon, (Goshen P. O.,) in the county of Lincoln and State of Georgia, have invented certain new and useful Improvements in Grinding-Mills, of which the following is a full, clear, and exact description.

In grinding wheat or other substances in mills of the character herein shown a part of the weight of the runner rests on the bridgetree and a part is held up by the reaction of or on the substance being ground, and if the pressure on the grain be constant a uniform velocity of the runner would insurea uniform reduction or grinding. As the slightest rise or fall of the runner makes a material difference in the coarseness or fineness of the grist, the lengthwise expansion and contraction of the runner-spindle under different temperatures of the air and different degrees of heat generated while the mill is grinding must be compensated for, and when the ordinary nut and screw are used to raise or lower the runner-spindle to regulate the grinding the constant attention of the miller is required.

It is the object of my invention to provide a mill in which the runner shall be adjusted automatically,so as to insure a uniform grinding, thus allowing the miller to give his attention to other duties about the mill or to more runs of stones than otherwise would be possible, and to allow the grinding to be done with the aid of comparatively unskilled attendants, and consequently cheaper labor.

The invention consists in certain novel features of construction and combination of parts of the grinding-mill, all as hereinafter fully described and claimed.

Reference is to be had to the accompanying drawings, forming part of this specification,

' in which similar letters of reference indicate Serial No. 173,397. (No model.)

mill. The runner A is fixed to the spindle D, which carries the driving-pulley E, and is stepped, as at d, in the bridge-tree F, which is fulcrumed at its end f in a notch or bearing on or in the mill-frame, and at-its other end, which also lies in a notch in the mill-frame, is connected by a rod, G, to a suitable link or hook, H, which hangs from a pin, I, fixed in the scale-beam or lever J, which is suspended by a link, K, (which engages a pin, L, in the beam,) from a cross-piece or rod, M, held in standards N, rising from the mill-frame. On the long arm of the beam J is placed a weight or counterpoise, O, which may be moved along the beam and set into or at any one of a series of notches, j, in the beam.

The distance between the two pivots I L should be or preferably is such that the rocking movement of the beam J will be slight between its extremes of motion in compensating for the expansion and contraction of the spindle, and the length of the beam will be such that when the weight 0 is placed at or near the outer end of the long arm of the beam the weight will about balance the weight of the bridge-tree and runner-stone.

By the arrangement of the beam directly over the vertically-movable end of the bridgetree, and by its direct connection with the bridge-tree, and so that the center of gravity of the beam is also its center of motion, and by suspending the bridge-tree from the beam and the beam from the mill-frame by practically knife-edge bearings having very little friction, a delicate balance of the parts is secured, so that as the weight 0 is moved inward on the beam toward the pivots more and more of the weight of the runner will become effective in grinding, and the proportional part of the weight of the runner on the bed-stone with any given'position of the weight on the beam will remain the same during the process of grinding, and the beam will rise and fall and adjust itself automatically to the slightest variation in the length of the spindle, caused by its expansion or contraction, so as to insure a uniform grist when once the weight 0 is set properly on the beam.

It is evident that the construction is very simple, inexpensive, and durable, as but a single weighted scale-beam and a connection lever, and alink-and-rod connection',HG,ber0 therefrom to the bridge-tree'are employed I tween the pin Ion the lever and theabridge- Having thus described my invention, what tree, said link K connecting with asu'pport of I claim as new, and desire to secure by Letters 5 Patent, is

In a grinding-mill, the combination, with the bed-stone B, bridge-tree F, spindle D, and upper runner, A, of a lever, J a link, K, and pins I L M, an adjustable weight, 0, on said the mill-frame and with the pin L of the lever J, substantially as herein set forth.

BENJAMIN J. DU BOSE.

Witnesses: r

E. B. OADE, R. I. WALTON. 

